Injuries to the neck, especially flexion and extension (whiplash) injuries, cause joint, ligament, and muscle disfunctions that can limit motions of one or more of the spinal joints. Referring initially to FIGS. 1-4, shown in FIG. 1 is the balanced position of the head 20 with the skull 22 on the lateral upright cervical vertebral column 24. The head 20 is in equilibrium when the eyes 26 look horizontally, as shown by axis A. With the head 20 in this position, the plane of the bite, shown as axis B, is also horizontal, or parallel to axis A. Force is produced by the weight of the head 20 through its center of gravity lying at the front of the sella turcicia, which is shown as the intersection C of the gravity force line D and the horizontal axis A. The gravity force line D extends from the intersection C with the horizontal axis A through the anterior one-third of the C4-C5 disk.
The angle of the normal cervical spine lateral curve is measured between axis lines E of the posterior border of the C2 vertebra and the axis line F off the posterior border of the C7 vertebra. Normally, the intersection of the axis lines E and F should form an acute angle in the range of about 43° to 45°.
Referring to FIG. 2, the skull 22 and the cervical vertebral column 24 normally each have 7.5 degrees of forward flexion and 7.5 degrees of backward extension movement relative to the vertebrae below, producing 130 degrees of total flexion of the skull and neck.
Referring to FIGS. 3 and 4, FIG. 3 shows a representation of an x-ray of an injured skull 26 and cervical spine 28. The center of gravity line D is reproduced to show the displacement of the cervical spine 28 from its normal position. In this case, the cervical spine 28 is displaced from its normal position relative to the center of gravity line D by approximately 1-¼ inch as shown in FIG. 3. There is a need for a device that can help restore the cervical spine 48 to a normal or substantially normal position as shown in FIG. 4.